GetServices and GetControllers

[Sleitnick]

• Adds GetServices() and GetControllers() methods.
• Freeze services and controllers tables.

Note: This does not include the client-side services table. In other words, GetServices() is a server-only method & not available on the client. Items in this table are lazy-initialized as accessed, and require lookup into the data model. Thus, there is no adequate way to get all of them with the current setup.

[SigmaThetaTech]

These changes provide the flexibility I need to query all modules in my framework for certain properties while also protecting the framework's controllers and services tables from mutations at runtime with table.freeze().

Asserting that Knit has started when calling these methods is an adequate solution, perhaps even favorable over returning a promise since Knit.OnStart() is already a provided promise.

Overall seems like a good solution that gives more flexibility. Thank you!